ST. LOUIS -- Teams anticipating high-90s heat from Cardinals closer Trevor Rosenthal may have to revisit those scouting reports, as Rosenthal has increasingly shown that he is willing to go away from his fastball to keep some guesswork in play.

That was no more evident than on Monday, when Rosenthal opened the ninth by throwing 10 straight offspeed pitches (five changeups, five curveballs) as he tried to preserve a one-run lead. It was a deliberate move to try and outwit the Pirates, who had just faced Rosenthal six days earlier.

In that last outing, Andrew McCutchen had jumped on a first-pitch fastball for a home run.

"Trevor went right into the hornet's nest against some guys who have hit him well," manager Mike Matheny said. "And I guess your rationale is, 'Well, do we keep doing what we've been doing? Or do we try to do something different and show them a different repertoire?'

"He was a flamethrowing fastball pitcher when he first came up and took over that [closer] position. Now he's a guy who can throw a curveball in there for a strike when he wants to. He can throw a behind-in-the-count changeup. Reminding a big lineup over there and showing them those other things, it can possibly help keep them in between, because those are pitches he can make in those counts."

On Monday, Rosenthal retired McCutchen with a curve and Neil Walker with a changeup. He closed the 17-pitch outing with seven straight fastballs, the last a 99-mph one that Gaby Sanchez swung through to give Rosenthal his 41st save of the season.

The sequence was a variation for Rosenthal, who has thrown 79 percent fastballs this season. The curveball, which accounts for only four percent of his season pitches, has been used with more frequency as of late.

"To watch one right after the other was impressive," Matheny said. "They weren't just sloppy secondary pitches. They were quality secondary pitches. Not just these guys, but everybody in the league, the next guys we're going to face are watching video and will be like, 'What is that?' Then he reaches back and hits 97."